5 Adventures That'll Make Your Stomach Drop

Weightlessness. It sounds like such a calm and peaceful state. But the best way to have this experience here on Earth can actually be very hard on the stomach.

To see what weightlessness is like without taking a trip into space, board G-FORCE ONE, a modified Boeing 727 owned by the Arlington, Va.-based company, ZERO-G. The plane gives its passengers the feeling of weightlessness by making a series of aerobatic maneuvers known as parabolas. To perform this stunt, the pilot climbs to 24,000 feet (7,315 meters) then gradually turns the nose of the plane up until it's flying at a 45-degree angle. When the plane reaches 34,000 feet (10,363 meters), the pilot turns the nose down, flattening out again at 24,000 feet before repeating. The result is a flight pattern with peaks and valleys that looks like a wave. As the plane descends from the top of the wave to the bottom, passengers experience weightlessness. From the bottom to the top, however, they're exposed to a g-force of 1.8 [source: Zero G].

If you have a weak stomach, just the description of this flight will make yours turn. Perhaps that's why NASA's version of the G-FORCE ONE earned the nickname "Vomit Comet."

Which Is It: Zero G or Weightlessness?

The company's name, ZERO-G, is a bit misleading. Gravity is very much at work during the flights of the G-FORCE ONE. Passengers float inside the aircraft as if weightless because they are basically being pulled toward Earth at the same rate as the plane. If someone on the ground could see the people on board, it would look like they were falling, not floating.